Use of recycled plastics for preparing high performance composite railroad ties
AssigneePolywood Inc.
InventorsThomas Nosker, Richard Renfree, James Kerstein
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Abstract
A method of maintaining proper distance between railroad rails is disclosed. The method utilizes railroad ties manufactured from a composite of polystyrene and polyolefin components, preferably obtained from recycled plastics. The composite exhibits a dual phase morphology wherein the two phases, polystyrene and polyolefin, intertwine and remain continuous throughout the material.
Claims24
In a method of maintaining spacing between railroad rails by attachment of said rails to at least one railroad tie, the improvement wherein:
- said at least one railroad tie is formed from a plastic composite material comprising 20-50 wt % of a polystyrene component forming a first phase and 50-80 wt % of a polyolefin component forming a second phase,
- wherein said polystyrene component contains at least 90 wt % polystyrene and said polyolefin component contains at least 75 wt % high density polyethylene, and
- wherein said first phase and said second phase each form three dimensional networks that are integrated with one another within said composite material.
In a method of providing a weight bearing support surface for railroad rails by attachment of said rails to at least one railroad tie, the improvement wherein:
- said at least one railroad tie is formed from a plastic composite material comprising 20-50 wt % of a polystyrene component forming a first phase and 50-80 wt % of a polyolefin component forming a second phase,
- wherein said polystyrene component contains at least 90wt % polystyrene and said polyolefin component contains at least 75 wt. % high density polyethylene, and
- wherein said first phase and said second phase each form three dimensional networks that are integrated with one another within said composite material.
In a method of maintaining spacing between railroad rails by attachment of said rails to at least one railroad tie, the improvement wherein:
- said at least one railroad tie is formed by extruding a plastic melt blend containing a polystyrene component forming a first phase and a polyolefin component forming a second phase,
- wherein, within said plastic melt blend, the ratio of the viscosity of the polystyrene component to the viscosity of the polyolefin component is approximately equal to the ratio of the volume of the polystyrene component to the volume of the polyolefin component, and
- wherein said first phase and said second phase each form three dimensional networks that are integrated with one another within said composite material.
Dependencies are inferred from the claim text.